In the case of complex machines it is often necessary for electrical energy to be passed to regions which are far away from the current source or the current connection terminal of the machine. In practice that is very extensively effected by the use of cables. If however the cables are passed along the outside of the machine, they can impede the working region. Furthermore in the case of handling operations in the region of the machine the cables can be damaged and thus represent a risk in regard to the maintenance and/or operating personnel.
Thus for example in the case of a sausage clipping machine it is necessary for the electric motor for a discharge conveyor belt to be connected by way of a cable to the current connection terminal of the machine. In that situation the cable is laid relatively loosely as the discharge conveyor belt is mounted pivotably or rotatably to the machine housing of the clipping machine in order to permit access to the displacement and clipping unit of the clipping machine.
German laid-open application No 199 12 000 discloses a rotary bearing of the kind set forth in the opening part of this specification, which has a bearing casing of electrically conductive material and a bearing shaft rotatably mounted in the bearing casing. Provided in the bearing casing and the bearing shaft is a current path bolt which is arranged in coaxial relationship with the longitudinal center line of the rotary bearing and which has a connection terminal lug at its one end and a contacting pin at its other end. That known rotary bearing is provided in the form of a plug connector for a mobile telephone. For the purposes of separating the bearing casing from the bearing shaft the entire rotary bearing has to be broken down into its individual parts.
German patent No 20 47 456 discloses a connecting portion for electrically conductingly fixing a connecting cable to a counterpart portion with a contact pin connected to the connecting cable and a permanent magnet which is disposed on the counterpart portion in the area around the contact pin. In that arrangement the contact pin is supported rotatably and displaceably in the axial direction in a holder which is connected to the permanent magnet, wherein a spring which presses the contact pin against the counterpart portion is arranged between the holder and the contact pin.
In addition German laid-open application No 25 38 766 discloses an electrical rotary contact which includes: a carrier disk with a bore, a respective contact disk on each side of the carrier disk with further bores arranged on the same axis with respect to the bore of the carrier disk, a cable connecting portion with an electrically conducting projection, wherein the projection is passed with the interposition of an insulating ring through an electrically conducting ring and through the bores in the carrier disk and the contact disks, and a resilient element for pressing the electrically conducting ring against the one contact disk and for making an electrical connection between the projection and the other contact disk.
German Utility Model No 297 17 068 discloses a door comprising a frame and a door leaf which is hingedly connected to the frame by one or more hinge plates.
Finally German patent specification No 41 25 949 also discloses an apparatus for forming loops on a sausage clipping machine.